66716591 has 2 divisors, whose sum is σ = 66716592. Its totient is φ = 66716590.

The previous prime is 66716579. The next prime is 66716603. The reversal of 66716591 is 19561766.

It is a balanced prime because it is at equal distance from previous prime (66716579) and next prime (66716603).

It is a cyclic number.

It is not a de Polignac number, because 66716591 - 2¹⁰ = 66715567 is a prime.

It is a super-2 number, since 2×66716591² = 8902207029322562, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66716561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33358295 + 33358296.

It is an arithmetic number, because the mean of its divisors is an integer number (33358296).

Almost surely, 2^66716591 is an apocalyptic number.

66716591 is a deficient number, since it is larger than the sum of its proper divisors (1).

66716591 is an equidigital number, since it uses as much as digits as its factorization.

66716591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 66716591 is about 8168.0224656890. The cubic root of 66716591 is about 405.5813244095.

The spelling of 66716591 in words is "sixty-six million, seven hundred sixteen thousand, five hundred ninety-one".